scholarly journals Radio Power from Direct-collapse Black Holes

2021 ◽  
Vol 922 (2) ◽  
pp. L39
Author(s):  
Daniel J. Whalen ◽  
Mar Mezcua ◽  
Samuel J. Patrick ◽  
Avery Meiksin ◽  
Muhammad A. Latif
Keyword(s):  
Black Holes ◽  
Near Infrared ◽  
Space Telescope ◽  
Very Large Array ◽  
Black Hole Accretion ◽  
James Webb Space Telescope ◽  
New Radio ◽  
Sky Survey ◽  
The Universe ◽  
Radio Power

Abstract Direct-collapse black holes (DCBHs) forming at z ∼ 20 are currently the leading candidates for the seeds of the first quasars, over 200 of which have now been found at z > 6. Recent studies suggest that DCBHs could be detected in the near-infrared by the James Webb Space Telescope, Euclid, and the Roman Space Telescope. However, new radio telescopes with unprecedented sensitivities such as the Square Kilometre Array (SKA) and the Next-Generation Very Large Array (ngVLA) may open another window on the properties of DCBHs in the coming decade. Here we estimate the radio flux from DCBHs at birth at z = 8–20 with several fundamental planes of black hole accretion. We find that they could be detected at z ∼ 8 by the SKA-FIN all-sky survey. Furthermore, SKA and ngVLA could discover 106–107 M ⊙ BHs out to z ∼ 20, probing the formation pathways of the first quasars in the universe.

scholarly journals On the detection of supermassive primordial stars – II. Blue supergiants

2019 ◽  
Vol 488 (3) ◽  
pp. 3995-4003 ◽  
Author(s):  
Marco Surace ◽  
Erik Zackrisson ◽  
Daniel J Whalen ◽  
Tilman Hartwig ◽  
S C O Glover ◽  
...  
Keyword(s):  
Gravitational Lensing ◽  
Near Infrared ◽  
Detection Limits ◽  
Wide Field ◽  
Spectral Features ◽  
Field Surveys ◽  
Space Telescope ◽  
Surface Temperatures ◽  
James Webb Space Telescope ◽  
The Universe

ABSTRACT Supermassive primordial stars in hot, atomically cooling haloes at z ∼ 15–20 may have given birth to the first quasars in the Universe. Most simulations of these rapidly accreting stars suggest that they are red, cool hypergiants, but more recent models indicate that some may have been bluer and hotter, with surface temperatures of 20 000–40 000 K. These stars have spectral features that are quite distinct from those of cooler stars and may have different detection limits in the near-infrared today. Here, we present spectra and AB magnitudes for hot, blue supermassive primordial stars calculated with the tlusty and cloudy codes. We find that photometric detections of these stars by the James Webb Space Telescope will be limited to z ≲ 10–12, lower redshifts than those at which red stars can be found, because of quenching by their accretion envelopes. With moderate gravitational lensing, Euclid and the Wide-Field Infrared Space Telescope could detect blue supermassive stars out to similar redshifts in wide-field surveys.

scholarly journals Fracture of Be and Its Alloys - Webb Space Telescope Revisited

2021 ◽  
Author(s):  
Muhammad Musaddique Ali Rafique
Keyword(s):  
Near Infrared ◽  
Joint Venture ◽  
Coefficient Of Thermal Expansion ◽  
Infrared Range ◽  
Linear Coefficient ◽  
Space Telescope ◽  
Hexagonal Close Packed ◽  
James Webb Space Telescope ◽  
Layer Deposition ◽  
Slip Planes

NASA/ESA/CSA joint venture James Webb Space Telescope is about to be launched. It is hypothesized to operate in near-infrared range. It is also hypothesized to unveil early star formation, galaxies, and universe due to its orbit, point in orbit and orbital motion. It has been under manufacturing for over 20 years at a staggering cost of 10 billion US dollars (most expensive scientific experiment in history). Beryllium (Be) is chosen to be element for construction of its main mirrors due to its high stiffness, low density, low linear coefficient of thermal expansion (α) in cryogenics and high thermal conductivity. It is followed by gold (Au) layer deposition on its (Be) surface to enhance its sensitivity towards infrared radiation as later is hypothesized to bear superior properties. However, serious mistakes have been made in selecting this material for this application. Owing to its crystal structure (hexagonal close packed (hcp)), slip planes (basal, prismatic and pyramidal) and mechanisms of their activation, Be necessitates easy fracture at cryogenic temperature. It has anisotropic properties and prone to transverse fracture under tensile loading. Furthermore, its ductile to brittle transition temperature is very low making it entirely unsuitable for such an application. It is one of most expensive metals on planet. This study constitutes revisiting these fundamental properties and mechanisms which were entirely ignored during materials selection thus rendering whole project useless.

Detectors for the James Webb Space Telescope near infrared spectrograph (NIRSpec)

2006 ◽  
Author(s):  
Bernard J. Rauscher ◽  
Torsten Böker ◽  
Craig Cabelli ◽  
Guido De Marchi ◽  
Pierre Ferruit ◽  
...  
Keyword(s):  
Near Infrared ◽  
Space Telescope ◽  
James Webb Space Telescope

scholarly journals WATCAT: a tale of wide-angle tailed radio galaxies

2019 ◽  
Vol 626 ◽  
pp. A8 ◽  
Author(s):  
V. Missaglia ◽  
F. Massaro ◽  
A. Capetti ◽  
M. Paolillo ◽  
R. P. Kraft ◽  
...  
Keyword(s):  
Radio Galaxies ◽  
Sloan Digital Sky Survey ◽  
Host Galaxy ◽  
Wide Angle ◽  
Host Galaxies ◽  
Very Large Array ◽  
Sky Survey ◽  
Black Hole Masses ◽  
Extended Emission ◽  
Radio Power

We present a catalog of 47 wide-angle tailed radio galaxies (WATs), the WATCAT, mainly built including a radio morphological classification; WATs were selected by combining observations from the National Radio Astronomy Observatory/Very Large Array Sky Survey (NVSS), the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST), and the Sloan Digital Sky Survey (SDSS). We included in the catalog only radio sources showing two-sided jets with two clear “warmspots” (i.e., jet knots as bright as 20% of the nucleus) lying on the opposite side of the radio core, and having classical extended emission resembling a plume beyond them. The catalog is limited to redshifts z ≤ 0.15, and lists only sources with radio emission extended beyond 30 kpc from the host galaxy. We found that host galaxies of WATCAT sources are all luminous (−20.5 ≳ Mr ≳ −23.7), red early-type galaxies with black hole masses in the range 108 ≲ MBH ≲ 109 M⊙. The spectroscopic classification indicates that they are all low-excitation galaxies (LEGs). Comparing WAT multifrequency properties with those of FR I and FR II radio galaxies at the same redshifts, we conclude that WATs show multifrequency properties remarkably similar to FR I radio galaxies, having radio power of typical FR IIs.

scholarly journals COMMISSION 28: GALAXIES

2007 ◽  
Vol 3 (T26B) ◽  
pp. 183-183
Author(s):  
Elaine M. Sadler ◽  
Françoise Combes ◽  
Sadanori Okamura ◽  
James J. Binney ◽  
Anthony P. Fairall ◽  
...  
Keyword(s):  
Black Holes ◽  
Galaxy Evolution ◽  
Web Site ◽  
Business Meeting ◽  
General Assembly ◽  
Spitzer Space Telescope ◽  
Space Telescope ◽  
Information Session ◽  
The Universe ◽  
Hubble Time

The members of Commission 28 on Galaxies were very busy during this General Assembly, with the Commission involved in two Symposia (IAU Symposium No. 235 Galaxy Evolution across the Hubble Time, IAU Symposium No. 238 Black Holes: from Stars to Galaxies), and two Joint Discussions (JD07 The Universe at z > 6, JD15 New Cosmology Results from the Spitzer Space Telescope). Therefore, the Business Meeting was combined with the Division VIII Business Meeting, which included a short information session on the new Commission 28 Organizing Committee. The triennial report of the Commission for 2003-2005 was also distributed, and is available on the Commission 28 web site.

scholarly journals Maximizing the power of deep extragalactic imaging surveys with the James Webb Space Telescope

2019 ◽  
Vol 486 (3) ◽  
pp. 3087-3104 ◽  
Author(s):  
T W Kemp ◽  
J S Dunlop ◽  
R J McLure ◽  
C Schreiber ◽  
A C Carnall ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Parallel Imaging ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Current Knowledge ◽  
Signal To Noise Ratio ◽  
Added Value ◽  
Space Telescope ◽  
James Webb Space Telescope ◽  
The Impact

Abstract We present a new analysis of the potential power of deep, near-infrared, imaging surveys with the James Webb Space Telescope (JWST) to improve our knowledge of galaxy evolution. In this work we properly simulate what can be achieved with realistic survey strategies, and utilize rigorous signal-to-noise ratio calculations to calculate the resulting posterior constraints on the physical properties of galaxies. We explore a broad range of assumed input galaxy types (>20 000 models, including extremely dusty objects) across a wide redshift range (out to z ≃ 12), while at the same time considering a realistic mix of galaxy properties based on our current knowledge of the evolving population (as quantified through the Empirical Galaxy Generator). While our main focus is on imaging surveys with NIRCam, spanning $\lambda _{\mathrm{ obs}} = 0.8\!-\!5.0\, \mu$m, an important goal of this work is to quantify the impact/added-value of: (i) parallel imaging observations with MIRI at longer wavelengths, and (ii) deeper supporting optical/UV imaging with HST (potentially prior to JWST launch) in maximizing the power and robustness of a major extragalactic NIRCam survey. We show that MIRI parallel 7.7-$\mu$m imaging is of most value for better constraining the redshifts and stellar masses of the dustiest (AV > 3) galaxies, while deep B-band imaging (reaching ≃ 28.5 AB mag) with ACS on HST is vital for determining the redshifts of the large numbers of faint/low-mass, z < 5 galaxies that will be detected in a deep JWST NIRCam survey.

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